<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>

<body>
  <div id="app">
    <ul>
      <li v-for="item of arr" :key="item.brand">
        {{ item.brand }}
        <ol>
          <li v-for="(itm, idx) of item.list" :key="index">
            {{ itm }}
          </li>
        </ol>
      </li>
    </ul>
    <ul>
      <li v-for="item of str">{{item}}</li>
    </ul>
  </div>
</body>
<script src="lib/vue.js"></script>
<script>
  const vm = new Vue({
    el: '#app',
    data: {
      str: 'abcdefg',
      arr: [
        {
          brand: '宝马',
          list: [
            'X5', 'X6'
          ]
        },
        {
          brand: '奥迪',
          list: [
            'A8', 'A6'
          ]
        },
        {
          brand: '奔驰',
          list: [
            'S500', 'S686'
          ]
        }
      ]
    }
  })

</script>

</html>